The disc set worked perfectly, and I was able to recover an X40 I bought from eBay to its factory configuration. I ran into one hiccup: I could not continue into Windows XP without product activation. My X40 was of the correct machine type and model number for this recovery disc set; however, product activation was not automatic, either because the disc set was actually encoded for the OP's machine (given that the auto-filled XP Pro product key was different from my machine's XP Pro product key), or OEM activation was not an automatic process at the time. Because MS no longer supports online Windows XP activation, we have to resort to an unorthodox way of activating Windows XP using the registry (booting Windows into "Safe Mode with Command Prompt," running regedit, resetting the activation timer and setting a specific key in the registry--Uncle Google is helpful here). The registry method appears to have worked, but I'm not yet sure of its long-term effects. Otherwise, it works perfectly, and this laptop, which was around before the term "ultrabook" was coined, sips power with its ultra-low voltage Pentium M at 1.2 GHz. It's a superb machine for Windows retrocoding with Visual Studio 2005.